frank-medium: pass --mmproj explicitly; this build has no autoload

The 36:29/327680/vision deploy came up healthy and text-only: image requests
answered 500 'image input is not supported - hint: ... provide the mmproj'
with no mmproj line in the load log, so llama-server fb27a525 does not
autoload mmproj*.gguf from the model directory. Name the file, the way
frank-small's serve script already does, and pin the flag in the seam.

scripts/serve-frank-medium.sh

@@ -161,8 +161,13 @@ TEMPLATE_ARGS+=(--chat-template-kwargs "$CHAT_TEMPLATE_KWARGS")
 PLACEMENT_ARGS=(--device "$DEVICES" --split-mode "$SPLIT_MODE" --tensor-split "$TENSOR_SPLIT")
 
 MMPROJ_ARGS=()
-[[ "$NO_MMPROJ" == "1" ]] && MMPROJ_ARGS=(--no-mmproj)
-
+if [[ "$NO_MMPROJ" == "1" ]]; then
+    MMPROJ_ARGS=(--no-mmproj)
+else
+    # No autoload in this build: a server without the flag starts text-only
+    # and answers image requests with a 500, so name the projector.
+    MMPROJ_ARGS=(--mmproj "$MM_PROJ")
+fi
 exec "$LLAMA_BIN" \
     --model "$MODEL" \
     --alias "$ALIAS" \